The fact that they waited 6 months seems to be pretty good evidence that the docs don't believe it is cancer. However, that being said, the only way to really know is to biopsy the lesion. So you have a decision to make; insist that the docs do a biopsy or take their word for what the lesion is. Of course, it is your life and if it is cancer and they miss it, you are the one who will have to live with it, not the docs.
Good luck in making your decision.
Joan L